1. Field of the Invention
This invention relates to a system for clearing the reflective surface of an external driving mirror of a vehicle. More particularly, the invention relates to a system and method for blowing compressed air onto side mirrors of a truck in order to clear debris and rain from the mirrors.
2. Description of the Related Art
The accumulation of dirt, precipitation, and/or any other substance on the reflective surface of a motor vehicle's external driving mirror is a common problem for operators of motor vehicles. This accumulation prevents and obstructs the operator's visibility to the rear and side of the vehicle. For example, such accumulation could inhibit the operator's ability to see any traffic approaching in an adjoining lane or any vehicles or other obstructions as the vehicle is traveling in reverse. Moisture will collect on the viewing surface of exterior rearview mirrors in heavy fog or rain. This condition has the ability to distort the reflective properties of the mirror and can be dangerous for a driver. This situation is further compounded during periods of darkness when the reflection of headlights upon the moisture covered rearview mirror creates additional visual distortion to images reflected by the mirror. The situation is most dangerous when the external driving mirrors are the only mirrors on the vehicle that provide the operator with visibility to the rear of the vehicle. Such is the case with many large trucks.
A number of solutions have been proposed in the prior art to solve the problem of clearing the rear view mirrors of dirt, water, and/or other substances. These solutions include both passive air deflectors and active air blowers. The first group consists of a variety of devices aimed at collecting the incoming air during the movement of a vehicle and projecting it onto the surface of the rear view mirror. Examples of such solutions can be found in U.S. Pat. Nos. 3,598,469; 4,869,581; 4,898,458; 4,903,581; 4,963,011; 4,979,809; 5,179,470; 5,343,328; 5,760,956; 5,815,315; and 5,868,867. These devices may have some use during a high speed movement of a vehicle; however, at low speeds or when the vehicle is not moving, these devices do not provide adequate air flow to clear the mirrors. Also, they are inherently incapable of conditioning the air flow such as to increase its temperature or reduce humidity, all of which may be helpful in extreme weather conditions.
The use of various active air blowers has also been described. However, many of these systems are overly complex and hence vehicle-specific. They assume incorporation of unique design elements with the on-board air-system of the vehicle and are not easily adapted to be used for a variety of different vehicles. In addition, in many cases the air blowers are underpowered and blow the air at an acute angle towards the surface of the mirror so that the incoming moist and cold air flow simply overwhelms their function. Examples of such devices can be found in the following U.S. Pat. Nos. 3,859,899; 3,877,780; 4,350,084; 4,439,013; 4,462,303; 4,561,732; 4,981,072; 5,383,054; 5,903,389; 5,953,158; and 6,012,817; as well as in a PCT application No. WO 88/00142 and a UK application No. 2,262,441A.
Therefore, the need exists for a system for cleaning an external driving mirror of a vehicle that can safely utilize a vehicle's existing air compressing device.